1. Field of the Invention
The present invention relates to an improved fire barrier fabric and its method of preparation.
2. Description of the Prior Art
In the United States in 1983, over 37,000 people were seriously injured in residential and institutional fires. Property damage due to the same fires amounted to six billion dollars. Another source of serious and fatal burn injuries are accidents involving vehicles. In addition, many serious burn injuries occur in vehicles which are caused by careless smoking or children playing with matches. Since many vehicular fires are enclosed within the metal shell of the car body, they reach very high temperatures in a short period of time.
Extensive research has been conducted by both government and industry to develop materials for home furnishings that are either non-flammable or retard flame propagation. Other important considerations are that the materials be functional, aesthetic and economical.
Standards such as DOT 302 have been promulgated for materials used in vehicles. DOT Standard 302 limits the rate of flame propagation for fabrics used in vehicles. However, it has been repeatedly demonstrated that the burning characteristics of a multi-component structure can not be predicted from the burning characteristics of the individual components.
The federal government has developed the "cigarette burn test" to rate upholstery fabrics. However, certain fabrics that will not ignite from a smoldering cigarette (class 1 fabrics), can burn in contact with an open flame and allow the underlying batting in a cushion or upholstered furnishing to ignite.
Fire retardant foam coatings for drapery liners and backcoatings for upholstery fabrics are commercially available. There are chemical treatments for apparel fabrics. However, at best, these materials are self-extinguishing when the flame source is removed. If the flame source is not removed, these materials will char, lose their integrity and allow the flame to reach materials under the fabric coating.
Plasticized polyvinyl chloride (vinyl) and polyurethanes are extensively used for upholstery fabrics especially in transportation vehicles, kitchen furniture, furnishings in restaurants, theaters, night clubs and public buildings. These fabrics are inexpensive, long wearing, easy to clean and can be produced in a wide variety of textures, colors and weights.
Such fabrics usually consist of a cotton, polyester or polyester/cotton scrim to which is bonded a layer of vinyl or urethane. The scrim fabric can be woven, knit or non-woven and is usually a lightweight open fabric designed to provide dimensional stability, tensile strength and tear resistance to the composite fabric. The vinyl (where term "vinyl" is used, polyurethane would be equally applicable) can be extrusion coated onto the scrim or can be cast as a separate film and subsequently bonded to the scrim by stitch bonding, adhesive bonding, or heat bonding.
A typical vinyl upholstered chair consists of a metal, wood or plastic frame. The seat consists of a plywood base, a two to three inch thick slab of polyurethane foam and vinyl fabric enclosing the foam and stapled to the bottom of the wood base. Seats in vehicles such as school buses and subway cars are of similar construction. In automobiles, metal springs replace the plywood.
By proper selection of plasticizer and fire retardant fillers such as antimony oxide, self-extinguishing vinyl fabric can be produced. However, in the presence of a flame, the vinyl can shrink and expose the underlying material, usually urethane foam or polyester fiberfill. When these materials ignite, the entire chair or seat will be quickly engulfed in flames.
U.S. Pat. No. 4,526,830 to Fergizer relates to coated glass fiber fabrics suitable for use as mattress tickings. The fabrics comprise a woven or non-woven glass fiber fabric to which a layer of polymeric coating composition has been applied. The polymeric carrier can also include a fungicide, bactericide, flame retardant and filler.
U.S. Pat. No. 2,956,917 to Fasano discloses the impregnation of a loosely woven glass fabric in a solution of a polyalkyl methacrylate and a vinyl resin polymer comprising predominantly vinyl chloride, to set or adhere the glass yarns to each other and prevent distortion of the weave pattern, and laminating a preformed vinyl resin film onto the treated fabric by means of pressure.
U.S. Pat. No. 2,215,061 to Alt discloses a fabric prepared by coating a woven glass fabric with a coating composition derived either from cellulose, a synthetic resin, a natural resin, or a protein.
U.S. Pat. No. 2,686,737 to Caroselli et al discloses coated glass fiber fabrics wherein the coating is a butadiene-acrylonitrile copolymer.
U.S. Pat. No. 3,490,985 to Marzocchi et al discloses decorated woven glass fabric produced by taking two different types of interwoven strands and applying a mixture of thermoplastic resin, foaming agent and plasticizer over areas of the fabric which include the two different types of strands. The foaming agent reacts to foam the mixture in situ about the adjacent portion of both types of strands to provide flexible raised areas of foamed resin. The foamed resin is poorly bonded to one type of strand but strongly coupled to the other.
U.S. Pat. No. 2,830,925 to Fennebresque discloses a plastic laminate for decorative purposes produced by incorporating into the laminate a pigmented fibrous material which can be made of glass fiber.